In a known yarn covering apparatus, a core yarn continuously supplied from a yarn package is passed through a covering yarn supply unit positioned between the core yarn package and a take-up unit and is combined with a covering yarn through an aperture in an eyelet element located between the covering yarn supply unit and the take-up unit. The covering yarn supply unit has a covering yarn package provided therein and is driven for continuous rotation about an axis aligned with the aperture in the eyelet element so that the covering yarn supplied from the yarn supply unit is caused to turn about the axis of rotation of the yarn supply unit and entwine around the core yarn being coveyed past the eyelet element.
A problem is encountered in a prior-art yarn covering apparatus of this nature in that the quantity of the covering yarn which can be stored in and supplied from the covering yarn supply unit is limited by the size of the supply unit while there is practically no limit to the quantity of the core yarn to be supplied from the core yarn supply package provided externally of the core yarn supply unit.
An object of the present invention is to provide an improved yarn covering apparatus which is free from such a problem.